The present invention relates to a portable radio terminal (or generally, mobile telecommunication terminal), and more particularly to a portable radio terminal that prevents illegal use even if the terminal is lost or stolen and, in addition, allows a user to start using it immediately after the terminal is returned to a user.
Conventionally, there has been a need for preventing illegal use of a lost or stolen portable terminal. For example, Japanese Patent Kokai Publication JP-A-8-314805 (xe2x80x9cIllegal-use prevention system and method for a portable radio terminalxe2x80x9d) discloses a technology for ensuring security as shown in FIG. 4. The technology disclosed in the above publication is that, if the user enters an invalid password a predetermined number of times in order to start the operation of a portable radio terminal 11, a notification indicating an illegal use is sent automatically to an information center 13 that manages the portable radio terminal 11. Then, the portable radio terminal 11, responding to the notification, encrypts internal data and sends it to the information center 13 to cause the center to create a backup copy. After that, the portable radio terminal 11 deletes all the internal data. The internal data includes personal data such as a directory or schedules.
However, problems have been encountered in the course of investigations toward the present invention. Namely, the technology described above involves a lot of work because it works with the information center. In addition, because all the internal data is erased after a backup copy is created, the user cannot start using the terminal immediately after the lost terminal is returned to the user.
In view of the foregoing, it is an object of the present invention to provide a novel portable terminal allowing the user to register a security password. That is, it is an object of the present invention to provide a portable terminal which, when the user has the terminal lost or stolen at a destination or outside his home or office, reduces the danger of some other user stealing internal data, that is, user-registered data.
It is a further object of the present invention to provide a novel portable terminal which also allows the user to start using the portable terminal immediately after the user recovers it.
To solve the above problem, the present invention provides a portable radio terminal comprising an off-memory in which a power-off time is stored, an on-memory in which a power-on time is stored, a difference memory in which a difference between the power-off time and the power-on is stored, a user data registration memory, and a portable terminal control unit, wherein, when a value stored in the difference memory reaches a predetermined time, the portable terminal control unit waits for a password to be entered and, in response to the password entered, erases contents of the user data registration memory.
According to another aspect of the present invention, if the value stored in said difference memory is smaller than the predetermined time, said portable terminal control unit accepts a password up to a predetermined number of times and, if the number of times the password is entered exceeds said predetermined number of times, erases the contents of said user data registration memory.
The user registration data generally includes a password.
Further, for activating the automatic data erasing system, the portable terminal control unit turns on power after another predetermined time has elapsed after the power is turned off.